Terra*Time is a program which tracks and displays the local time in asmany as 44 cities all around the globe. Unlike other programs of thistype, Terra*Time accounts not only for time zone effects but also fordaylight savings time at each city. Information is provided on afull-screen color non- graphics display. Windows and menu-drivencommands are used for program modifications. Program options provideusers with the ability to tailor the display for their specific needs.As many or as few cities as desired can be displayed. Military or 12hour clock can be selected and the layout of the world map can be variedto suit the user. Additional program features include time zonedifferences and great circle distances between cities and a specialalarm feature which can be set for any world city time.

HARDWARE REQUIREMENTS

This program is designed for IBM Personal Computers and closecompatibles. It will execute on the IBM-PC, PC-XT, and PC-jr. DOSVersion 2.1 or later is required. Terra*Time does not require an internalclock and will accept the time set by you during DOS boot-up. Ofcourse, the use of the internal clock will allow for automatictimekeeping.

Since the program relies extensively on color, a color monitor isrecommended. The program will run, however, unmodified, on the Compaq.Terra*Time requires about 64K of memory and does not require BASIC tooperate.

The first two files must reside on the current directory or path for theprogram to be accessible.

None of these files is copy-protected and it is suggested that a set ofbackup files be made and saved in a separate place with your otherarchive and backup files. Save all four files in their original stateto preserve initial program default settings and cities information andto have a complete package to provide to other users.

Terra*Time is executed from the current directory or path with thiscommand at the DOS prompt: TT

There are no optional arguments.

PROGRAM START-UP

Upon execution, Terra*Time will load from the current directory and accessthe TT.DAT data file to load current settings and cities information.Once the program and data are loaded, the program no longer requiresthese files unless a new configuration is saved to disk for future use.The program is virtually self-explanatory and uses menus extensively.The program will load into [AutoTime] mode incorporating the defaultvalues and cities information in TT.DAT at time of execution.

GENERAL PROGRAM FEATURES

Terra*Time generates a stylized world map with cities indicated by threeletter codes. The map is divided into 24 time zones each of which isfurther divided into three twenty-minute segments. One timezone,normally the one you are in, is specially designated as the "local"timezone. The local timezone (initially set by the program defaults toNew York) is indicated on the top scale by a magenta symbol. Time anddate details about the local time zone as indicated in the center of theblack area below the world map. The local time indication is standardtime if it is shown in yellow and daylight savings time if it is shownin brown.

The black background on the map itself indicates the portion of theglobe between 6PM and 6AM (that is, approximately "nighttime") and moveswith the time in twenty minute intervals. A gray band will appearmomentarily around the display border while the map is being updated.Cities are indicated on the map in bright yellow if they are presentlyon standard time and in brown if they are presently on daylight savingstime.

HOUR-DAY SCALE

Across the bottom of the world map is an hour-day scale with somefeatures in white and some in yellow. The white (upper) scale indicatesthe STANDARD time in that particular world zone. One point on this topscale is the yellow letter M which represents midnight; N indicatesnoon. The lower scale, in yellow, is in the form:

<< Sun | Sat >>

and is used to determine the day of the week for any time zone. Thesymbol | represents the International Date Line in the central PacificOcean. From this symbol to the left (west), it is Sunday until the M(midnight) symbol is encountered on the scale above. It is Saturdaytoward the east until the M symbol. Of course, the scale wraps aroundat the left and right edges of the map.

A WORD ABOUT TIME SYSTEMS

Terra*Time displays time using the standard US AM/PM 12 Hour Clock and theInternational (or Military) 24 Hour Clock. However, for simplicity, allINPUTS to Terra*Time must be given using the 24 Hour Clock (the same asDOS). Some examples of the relationships between the two systems areshown below:

The ACTUAL local time (whether daylight or standard) should be input andTerra*Time will take care of the rest. If you have an internal computerclock, you must set it forward and back during switches between daylightand standard time just as you do with your other clocks.

Some computers have clocks that lose the seconds when time is reset.For example, the time 10:15:53 would be set to 10:15:00 and 53 secondswould be lost. In these cases time adjustments should be made justafter the minute has turned to minimize time loss effect.

PROGRAM FEATURES

Terra*Time incorporates a number of special features and options which areexplained below. These features are accessed by selecting the letter[F] from the [AutoTime] mode.

CITY CODES

Some features require that a particular world city be identified. Eachcity has been assigned a three letter abbreviation. These abbreviationscan be changed to suit the user. For example, the code NYC could bechanged to JFK to represent Kennedy airport, or to HQ, for CorporateHeadquarters (Three letters is a maximum for this code). It could evenbe altered to HFD, for Hartford, Connecticut, a nearby city with thesame parameters as New York.

ALARM

The Terra*Time alarm can be set for a specific time in a specific worldcity. This could be the local time or the time in a foreign location.For example, assume that you are in New York. You can set the clock toring when it is 7PM (1900) in Paris without having to compute timedifferences simply by indicating PAR and 1900 when the alarm is set.Terra*Time keeps track of the timezones and any savings time that might bein effect at either city.

Activating the alarm will illuminate a note in the lower left corner ofthe screen. The alarm will ring at the appropriate time, chiming everyfive seconds for one minute or until any key is selected to stop it.The alarm will be turned off once it has rung and will have to beactivated again even to ring again at the same time on the next day.The command [Activate] will engage the alarm with the current settingsunchanged. The [LOC] city code can be used for local time alarm. Besure to input the alarm time in HHMM format, two digits for the hoursand two for the minutes using a 24 Hour clock.

TIMEZONES

The [TimeZones] feature allows you to check the number of hours(timezones) any city is ahead or behind any other. A base zone isinitially set to the local city but can be moved to any other city, onezone at a time, with the [W]est or [E]ast keys.

DISTANCES

Terra*Time can also compute the distance between any of the cities in theprogram database (not just those shown on the map). A listing of citiescan be selected. The distance shown is the "great circle distance,"which is the shortest distance between the two points on a globe. Thisdistance is provided in statute miles (ordinary measure) or in nauticalmiles, a system used extensively in navigation. One nautical mile isabout 1.151 statute miles.

TIMESET/DATESET

Times and dates must be valid and follow the format specified. Datescannot precede 1980 since DOS will not recognize any date before1-Jan-1980. Since the Local Time display also computes theday-of-the-week, this feature will allow the determination of theday-of-the-week on which some future date will occur, such as a birthdayor Christmas.

MAPSHIFT

The displayed map can be centered on the US, on Europe, or on the FarEast with this option. There is no effect on the time.

12/24 HOUR SELECTION

The times displayed with the cities on the map can be presented ineither US 12/Hr format or Intl 24/Hr format using this option.

LOCALZONE

Any city in the Terra*Time city list can be designated the Local timecity. The Local Time strip in the black area below the map will take onthe attributes of this designated city and the LocalZone marker on thetop scale will move. When a new LocalZone is selected the times in allcities remain unchanged. Only the alarm, local time strip and otherfeatures using the local time are affected.

HELP COMMAND

A Help Screen with a Brief description of these features is available ina window within the [Settings] option of the program.

FILE COMMAND

When you have chosen a configuration of features and cities that youprefer, they can be saved to the TT.DAT file and subsequentlyautomatically loaded with the program. Any changes made in programfeatures or options will be in effect only for the remainder of thecurrent session unless they are saved with the [File] command. Once anew configuration is saved (in file TT.DAT) the previous configurationis lost. Be sure a backup copy of the original program and data fileshas been saved in case you want to start over or reinstate the originaloptions. A file called TTDAT.BAK is provided as a backup duplicate ofthe original TT.DAT file. Ensure that the file containing theinformation to be displayed is called TT.DAT before the program is run.

CITIES COMMAND

The [Cities] settings command allows the user to see and change theattributes of the cities provided in the Terra*Time database. Forexample, any city can be excluded or included from the map display. Thefollowing information about each city is displayed and can be altered asindicated.

CODE - The city code is a one to three letter designation. This code isused to identify the city on the map and to select and save cityfeatures. Any code except LOC can be selected. For example, NYC couldbe replaced by MAN (for Manhattan).

INCLUDE/EXCLUDE - If this parameter is set to INCL, the city is includedin the map display; if EXCL is selected, the city will not be displayed.The [List] command will provide a list of all of the cities in theTerra*Time database, indicating whether or not they are included in thedisplay. Although the default settings do NOT include all of thecities, all cities are designed to fit on the display map withoutoverlap (although leaving a somewhat cluttered appearance).

ZONE - The zone parameter represents the number of timezones east(positive) or west (negative) of the Prime Meridian (Greenwich, England)that the subject city lies. For example New York Zone is -5.0 and Parisis 1.0. Some cities are in timezones which are not an exact integernumber of hours from GMT (Greenwich Mean Time). Bombay, India, forexample, is 5 and one-half hours ahead of GMT. Its zone is indicated as5.30, with the 30 indicating 30 minutes more advance than five hours.The zone parameter is for information purposes and should not ordinarilybe changed.

DAYLIGHT

This parameter is either 1 (if Daylight Savings Time is ever applicableto this city) or 0 (if is not).

START

This is a four digit value which indicates the month and day that is thefirst day of daylight savings time. It is specified in the form MMDD,so 0531 would mean May 31st is the first day of daylight savings time.DD can be specified as 00 to indicate that the day should be the lastSunday of that particular month; for example 0400 would mean thatdaylight savings time should start the last Sunday of April.

END

This value indicates the LAST day of daylight savings time. Otherwise,the comments indicated above for START apply. Note that it is possiblefor the END date to precede the START date when summer comes in themonths of December, January and February as it does in the Southernhemisphere.

DAYLIGHT SAVINGS TIME

Daylight savings time is a convenience adopted by many localities duringthe summer months depending upon their particular needs and theirgeographic location. The information provided for the cities inTerra*Time was accurate for 1987-1988. But these rules are subject tochange depending upon legislation in each country. For this reasonTerra*Time allows the changing and saving of information relating todaylight savings time in the [Cities] menu. Data regarding country timezones and daylight savings time rules is available from the locallibrary or in a reference called the Official Airline Guide (copyrightReuben Donnelly & Co.) which is published monthly and used by mosttravel agents in the United States.

ADVANCED PROGRAMMING CONSIDERATIONS

Terra*Time is compiled in Basic and reads all of the city information aswell as the default settings from an ASCII file called TT.DAT. Thisfile can be editted with any text editor. The first line of the datafile contains a 30 character header which will appear centered on thetop portion of the display. This line can be revised to display anyheading the user desires. The next two lines of the file containdefault settings, followed by 44 lines of city data and a terminatingline. Only advanced users should revise this file since its formattingis critical to ensure proper reading of the data by the program. Alwayskeep a backup copy just in case. There is little value to changing thesecond and third (default values) lines of this file, but it may beuseful to edit the cities data on the next 44 lines if extensiverevisions are desired. The format of some typical city data lines ispresented here:

A comma must delimit each field and the alpha characters must be inquotes as shown. The fields have the following meanings:

A => The city nameB => Code to include plotting on map for that city (1) or not (0)C => One to three letter city code for plotting on mapD => A code designating the horizontal plotting location of that cityE => A code designating the vertical plotting location of that cityF => The time zone from Greenwich, England, with eastbound positiveG => Code to indicate daylight savings time is applicable (1) or not (0)H => Code for start of daylight savings time (described in START above)I => Code for end of daylight savings time (described in END above)J => Latitude of city in Degrees and Minutes, with North positiveK => Longitude of city in Degrees and Minutes, with West positive

The 44 cities have been carefully selected and plotted so they remaintrue to their intended time zone but so that no two can overlap nomatter how they are displayed. Thus any or all cities can be displayedat once. Changing Code D or E will cause different plotting locationsand could result in overlaid data or program problems.

This program uses special functions from the excellent Advanced FunctionLibrary for the Basic Compiler called ADVBAS.LIB v3.4, (C) Thomas HanlinIII, Alexandria, VA, available on many bulletin boards.

Some copies of Terra*Time are distributed via an excellent self-extracting archive program called PKARC version 3.5, dated 27 April1987, and available from PKWARE, Inc., 7032 Ardara Avenue, Glendale, WI53209.

I hope Terra*Time will prove to be of value to you. Please contact theauthor with any problems, useful comments or suggestions at the addressat the top of this file.